Composite envelopes are used when it is desirable to wrap a large number of sheets or magazines in an envelope and for holding of advertising indicia or a removable packet.
Prior large flap envelopes having inserts required a ribbon placed about the inserts to hold them in place during folding of the large flap. This was due to the requirement for an inclined conveyor to enable the large flap to be formed. When the web was inclined in this procedure, the inserts placed upon the web would tend to slide off without some means of support, resulting in a shutdown of the assembly system while the inserts were restacked. The use of a ribbon to hold the inserts in place solved this problem but added an extra step to the procedure.
The use of two separate webs to form a package is known and generally described in the U.S. Pat. No. 3,411,263 of Smolderen. However, Smolderen is directed to a sealed package to prevent the entrance of light therein and does not recognize the advantage of applying a transparent cover layer to the first web to allow an individual to visually observe the interior contents of the package. Smolderen also does not account for variable thicknesses of his package.
In view of the foregoing it can be seen that there is a need for a new envelope and method and apparatus for its construction where in a single web can be used and separated into the first web and the second web to create a base web having bottom and top flaps and a cover web which allows the envelope to be readily formed on a flat conveyor. It can also be seen that an envelope formed of a lower wrap web and an upper web by the described method and apparatus can be used to make an envelope having a transparent wall for viewing the contents held therein.